There was really never a 6500K COB (or single emitter actually) that was "ideal" in a sense..
Usually either too yellow and not enough cyan.
That said there were some that were quite passable. Have some Luxeon Rebels off eek bay that certainly were acceptable and cheap:
10pcs PHILIPS LUMILEDS LUXEON Rebel ES 3W Cool White 6000-6500k High Power LED
That was 30W for $11..
The fresh fish COB was $18.31 for about the same wattage but need to add shipping to it.
Note that there is no real "lens" on the "fresh fish" COB 135 degrees but 50% of the light is in 118 degrees..
This may or may not be like "normal" diodes which usually just say 120 degrees for the most part.
Total angle at which 90% of total luminous flux is captured.
2. Viewing angle is the off axis angle from the LED centerline where the luminous intensity is ½ of the peak value.
To b honest.. never really thought about it too much..
Anyways a comparison of 3 COBs
4000k Luminous Devices high CRI chip
5000K SORRA violet pump COB (runs really hot BTW)
6500K fresh fish COB. (Really how can you resist..
WB was set at 6500k so all lower k's will appear slightly warmer than what your brain will see.. We are more flexible to tones..
NOTE: Corrected image.. just wasn't "fair" to the 4000k one..old as link